1h-imidazo(4,5-beta)pyridine derivatives

ABSTRACT

Ethers and esters of 1-hydroxy-2-(1,1-difluoroalkyl)-1Himidazo(4,5-b)pyridine compounds, useful as herbicides.

States aieni [191 Dohert June I, 1974 I 5 lI-I-IMIDAZO(4,5- BETA )PYRIDINE DERIVATIVES [56] References Cited [75] Inventor: George 0. P. Doherty, Greenfield, FOREIGN N S OR PLICATIONS 734,835 6/1968 Belgium 260/309.2 [73] Assignee: Eli Lilly and Company, Indianapolis, OTHER PUBLICATIONS Basic Principles of Organic Chemistry, Benjamin Pub- [22] Fil d; M 20, 1972 hers, Page 806, by Roberts et al., (I965)QD 251 [21] Appl. No.: 236,195 RS8 Related U.S. Application Data Primary Examiner-Alan L. Rotman [63] Continuation-impart of Ser. No. 181,638, Sept. 17, Afwrneyflgenf, Smith; Kathleen I971, abandoned, which is a continuation-in-part of R. Schmoyer Ser. No. 100,410, Dec. 21, 1970, abandoned.

5 U S Cl 260 296 H 260 294 8 C 260 294 9 [57] ABS CT 2] l 260/295 Ethers and esters of l-hydroxy-2-(l,l-difluoroalkyl)- [51] Int Cl C07; 31/42 lH-imidazo(4,5-b)pyridine compounds, useful as her- 58 Field of Search 260/294.8 c, 295 F; 296 H blades- 6 Claims, N0 Drawings 1H-IMIDAZO(4,5-BETA)PYRIDINE DERIVATIVES CROSSREFERENCE TO RELATED APPLICATION This is a continuation-in-part of my copending application Ser. No. 181,638, filed Sept. 17, 1971, and abandoned after the filing of this application; application Ser. No. 181,638 is in turn a continuation-in-part of my copending application Ser. No. 100,410, filed Dec. 21, 1970 and abandoned after the filing of application Ser. No. 181,638.

SUMMARY OF THE INVENTION The present invention is directed to ethers and esters of 1-hydroxy-2-( 1,1-difluoroalkyl)-1I-I-imidazo(4,5 b)pyridine compounds. These derivatives are of the following formula:

In the above and succeeding formulae throughout the present specification and claims, R represents hydrogen, chlorine, fluorine, difluoromethyl, perfiuoroalkyl of C -C or radical of the formula wherein each Z independently represents hydrogen or halogen and m represents or 1; R represents amino, halogen, nitro, cyano, loweralkyl of C -C perfluoroalkyl of C C CF Cl, -CF I-I, or loweralkylsulfonyl of C C subject to the limitations (1) that all R substituents together contain not more than 8 carbon atoms; (2) that not more than two R symbols represent loweralkylsulfonyl groups; and (3) that where two loweralkylsulfonyl groups are present, they are located at the 5- and 7-positions; n represents an integer of from 1 to 3, both inclusive; and R represents alkenyl of C C cycloalkyl of C -C benzyl;

. phenethyl;

. alkanoyl of C -C alkenoyl of C C carbamoyl of the formula wherein X represents oxygen or sulfur; and one R represents phenyl, loweralkyl of C -C or loweralkenyl of C C and the other R represents hydrogen, loweralkyl of C C or loweralkenyl of C C subject to the limitation that both R moieties taken together do not contain more than six carbon atoms, or both R moieties taken together represent straight-chain alkylene of C -C both inclusive; 9. radical of the formulae loweralkyl of C -C or HO. A.. W

wherein X is, as above, oxygen or sulfur. 10. radical of the formula wherein R represents methylene, ethylene, or vinylene, and n represents 0 or 1; 11. radical of the formulae vbs ts y a d substituted phenyl, wherein substituted phenyl is a phenyl radical bearing from 1-3 substituents, each of which is independently amino, nitro, chloro, methyl, or methoxy, and R represents loweralkylene of C -C both inclusive;

12. -SO R wherein R is loweralkyl as above defined, cycloalkyl of C -C phenyl, substituted phenyl as above defined, or benzyl;

1 3. tetrahydro-2-pyranyl.

The compounds so defined are useful as herbicides. In addition, they can be used as starting materials for a process which results in rearrangement or reduction depending on the reaction conditions employed.

DETAILED DESCRIPTION OF THE INVENTION In the present specification and claims, the term halogen is employed to designate bromine, chlorine, fluorine, and iodine, only. In the case of the loweralkyl, loweralkenyl, alkyl, alkenyl, alkanoyl, alkenoyl, and loweralkylene radicals, such radical can be branched or straight-chain.

An essential and distinguishing structural feature of the compounds of the present invention is the substituent at the 2-position (CF -R); representative such radicals include the following:

trifluoromethyl difluorochloromethyl pentafluoroethyl heptafluoro-n-propyl l 1 -difiuoro-n-propyl l 1 -difluoro-2-chloroethyl l 1-difluoro-2,3-dichloron-propyl 1 ,1-difluoro-3-bromo-n-propyl 1 ,l ,2-trifluoroethy1 1,1 ,2-trifluoro-n-propyl 1 ,1 ,2,3-tetrafluoro n-propyl 1 ,1-difluoro-2-bromo-3-chloro-n-propyl perfluoro-n-butyl perfluoro-n-pentyl perfluoro-n-hexyl 1 ,1 ,2,2-tetrafluoroethyl Preferred groups are trifluoromethyl, difluoromethyl, difluorochloromethyl, 1,1 ,2 ,2-tetrafluoroethyl, and pentafluoroethyl.

The compounds of the present invention are typically crystalline solids. They are prepared in standard procedures for the derivatization of hydroxy groups. Hence, those of the derivatives claimed herein which are ethers can be prepared by those procedures discussed in chapter 6 of Synthetic Organic Chemi try, by Wagner and Zook (John Wiley and Sons, lnc., New York, 1965). The same reference discusses various synthetic procedures which can be employed for the synthesis of those derivatives claimed herein which are carboxylic acid esters (chapter 14), carbamic acid esters (chapter 23), and sulfonic acid esters (chapter 37).

Generally, the compounds of the present invention are conveniently prepared by the reaction of the corresponding l-hydroxy compounds:

loweralkyl or loweralkenyl are more readily prepared by reacting the corresponding l-hydroxy-lH-imidazo(4,5-b)pyridine with an isocyanate of the formula O=N=C-loweralky1 or loweralkenyl The reaction is conducted in conventional procedures.

Likewise, the carboxylic ester compounds of the present invention other than the carbamate esters are often preferably prepared by reacting the desired carboxylic acid as its anhydride with the corresponding 1- hydroxy-lH-imidazo(4,5-b)pyridine starting compound. Furthermore, in the case of the present compounds which are esters, preparation is sometimes preferably carried out by reaction of the l-hydroxy-lH- imidazo(4,5-b)pyridine with an olefin; this is particularly preferred in the case of the tetrahydro-Z-pyranyl ether. The alkenyl ethers may also be preferably prepared by addition to an alkyne.

Yet other synthetic techniques can be used in the preparation of the compounds of the present invention; examples are the use of N ,N'-carbonyldiimidazole or N,N'-dicyclohexyldicarbodiimide (See Reagents for Organic Synthesis, Fieser and Fieser (John Wiley and Sons, 1967), pages 114 et seq. and 231 et seq., respectively.

The following examples illustrate the present inven tion and will enable those skilled in the art to practice the same.

EXAMPLE 1: l-METHOXY-6-CHLORO-2- (TRIFLUOROMETHYL)- l H-lMlDAZ O-( 4,5- b)PYR1DINE 1-Hydroxy-6-chloro-2-(trifluoromethyl )-l H- imidazo-(4,5-b)pyridine (5 grams), 8O milliliters of ac etone, 5 milliliters of methyl iodide, and 10 grams of anhydrous potassium carbonate were mixed, heated and refluxed with stirring for twelve hours. The reaction mixture was then filtered, evaporated and eluted off of a silica column with diethyl ether, yielding the desired 1-methoxy-6-chloro-2-( trifluo romethyl 1 H- imidazo(4,5-b)pyridine product. It was recrystallized from petroleum ether (boiling at 60-80C). The product so obtained melted at 912C.

Analysis,

Calc.: C, 38.20; H, 1.99; N, 16.70. Found: C, 37.92; H, 2.32; N, 16.75.

EXAMPLE 2: l-BENZYLOXY-6-CHLORO-2- (TRIFLUOROMETHYL) 1 H-lMlDAZO(4,5-

b)PYRlD1NE 1-Hydroxy-6-chloro-2-(trifl uoromethyl l H- imidazo-(4,5-b)pyridine (5 grams), 1O milliliters of benzyl bromide, 20 grams of anhydrous potassium carbonate, and 100 milliliters of ethanol were mixed, heated to reflux, and refluxed for one hour. The reaction mixture was then filtered, evaporated under vacuum, and extracted with diethyl ether. The extract was 111- tered and evaporated under vacuum yielding a dark oil which on standing crystallized as the desired 1- benzy1oxy-6chloro-2-( trifluoromethyl) 1H- imidazo(4,5-b)pyridine. It was recrystallized from a mixture of acetone and petroleum ether boiling at 60- C., m.p., 10709C.

Analysis,

Calc.: C, 51.31; H, 2.77; N, 12.82. Found: C, 51.54; H, 2.62; N, 13.12.

EXAMPLE 3'. l-ACETOXY-6CHLORO-2- (TR1FLUOROMETHYL)- l H-1MlDAZO-(4,5-

b)PYRlDlNE 1-Hydroxy-6-chloro-2-(trifluoromethyl )-l H- imidazo-(4,5-b)pyridine (5 grams), 25 milliliters of no etic anhydride and 0.1 milliliter of sulfuric acid were mixed with stirring at 25C. for fifteen minutes. The reaction mixture was then heated to reflux and refluxed for one-half hour, poured into ice with stirring, stirred for ten minutes and filtered. Filtration yielded the desired 1-acetoxy-6-chloro-2-(trifluoromethyl)-1H- imidazo(4,5-b)pyridine product as a solid. It was taken up in ether, dried over magnesium sulfate, and the ether evaporated. The product then melted at 10304C. Analysis,

Calc.: C, 38.65; H, 1.80; N, 15.02.

Found: C, 38.88; H, 1.92; N, 15.02.

EXAMPLE 4: l-OCTANOYLOXY-6-CHLORO-2- (TRlFLUOROMETHYL)-l H-lMlDAZO(4,5-

b)PYRlDlNE To 1 -hydroxy-6-chloro-2-(trifluoromethyl)-1H- imidazo-(4,5-b)pyridine (2.37 grams) in 5 milliliters of pyridine was added octanoyl chloride (1.63 grams). The addition was carried out portionwise with stirring and resulted in the precipitation of a white solid. The reaction mixture was set on a steam bath for twenty minutes, then poured over ice cold aqueous HCl. An oil separated and subsequently crystallized on vigorous stirring. This precipitate was removed by filtration, dissolved in ether, dried over magnesium sulfate, filtered, and ether removed by evaporation under vacuum. The substance was purified by distillation, m.p., 33.535.5- C.

Analysis,

Calc.: C, 49.52; H, 4.71; N, 11.55. Found: C, 49.81; H, 4.93; N, 11.29.

EXAMPLE 5: 1-(ALLYLCARBAMOYLOXY)-6-CHLORO-2- (TRIFLUOROMETHYL)-1H-IMIDAZO(4,5-

b )PYRIDINE l-Hydroxy-6-chloro-2-(trifluoromethyl)-1H- imidazo-(4,5-b)pyridine (4.6 grams) was dissolved in 10 milliliters of diethyl ether and 2.4 milliliters of allyl isocyanate added and the reaction mixture stirred at room temperature for thirty-six hours. The reaction mixture was then filtered yielding 4.75 grams of a white powder, the desired 1-(allylcarbamoyloxy)-6-chloro-2- (trifluoromethyl)-1H-imidazo(4,5-b)pyridine. An additional portion of the product was obtained by evaporating the filtrate. The combined products were recrystallized from a mixture of diethyl ether and petroleum ether boiling at 60-80C., m.p., about 210C. Analysis,

Calc.: C, 41.20; H, 2.51; N, 17.47.

Found: C, 41.42; H, 2.51; N, 17.25. EXAMPLE 6:

1-(METHYLSULFONYLOXY)-6-CHLORO-2- (TRIFLUOROMETHYL)-lH-IMlDAZO(4,5- b)PYRlDINE 1-Hydroxy-6-chloro-2-(trifluoromethyl)- 1 H- imidazo-(4,5-b)pyridine (5 grams) in milliliters of pyridine was cooled to 5C. with stirring and methylsulfonyl chloride (5 milliliters) was added in l-milliliter portions, maintaining the temperature at about 5C. After the addition was completed, the reaction mixture was stirred for two hours at 5l0C., then poured into 30 grams of ice and milliliters of concentrated hydrochloric acid. The desired 1-(methylsulfonyloxy)-6- chloro-2-( trifluoromethyl 1 H-imidazo( 4,5 -b )pyridine product precipitated and was separated by filtration and washed with water. The washed product was taken up in diethyl ether with a trace of acetone, dried over magnesium sulfate and the solvent evaporated under vacuum. The product so obtained melted at 136.7C.

Analysis,

Calc.: C, 30.44; H, 1.60; N, 13.31. Found: C, 30.48; H, 1.83; N, 13.00.

6-Amino-5 ,7-dibromo-2-trifluoromethyl- 1 -hydroxy- 1H-imidazo(4,5-b)pyridine (1 gram) was mixed and stirred for two hours with 2 milliliters of methyl iodide, 2 grams of potassium carbonate, and 10 milliliters of acetone. The reaction mixture was then diluted with about milliliters of ether and washed with five 15- milliliter portions of water. The ether layer was dried over magnesium sulfate and filtered with carbon, and the ether removed on a rotary evaporator. The resulting 1-methoxy-6-amino-5 ,7-dibromo-2- (trifluoromethyl)-1H-imidazo(4,5-b)pyridine product melted at 16972C. A portion was recrystallized from methanol, m.p., 177-8C. Analysis,

Calc.: C, 24.64; H, 1.29; N, 14.37.

Found: C, 24.96; H, 1.51; N, 14.48.

EXAMPLE 8:

1-( METHYLCARBAMOYLOXY )-6-CHLORO-5 ,7- DIBROMO-2-( TRIFLUOROMETHYL 1 H- lMlDAZO(4,5-b)PYRlDlNE 6-Chloro-5 ,7-dibromo-1-hydroxy-2- (trifluoromethyl)-1H-imidazo(4,5-b)pyridine (0.9 gram) was mixed with ether (15 milliliters) and methyl isocyanate (2 milliliters) and stirred for fifteen minutes. Triethylamine (0.01 milliliter) was added, and the solution became homogenous. It was permitted to stand for sixteen hours, diluted with 50 milliliters diethyl ether; washed with 0.5N HCl, water, and saturated NaCl; then dried over magnesium sulfate, and evaporated. The resulting 1-(methylcarbamoyloxy)-6-chloro-5,7- dibromo-2-(trifluoromethyl)-1H-imidazo(4,5- b)pyn'dine product was recrystallized from chloroform, m.p., 216C. Analysis,

Calc.: C, 23.89; H, 0.89; N, 12.38.

Found: C, 23.82; H, 0.90; N, 12.16.

EXAMPLES 9-61 Other representative compounds of the present invention, prepared in accordance with the foregoing teachings, including the following:

l-allyloxy-6-chloro-2-(trifluoromethyl)-1H- imidazo(4,5-b)pyridine, n 1.5204.

1-isopropoxy-6-chloro-2-(trifluoromethyl)-1H- imidazo(4,5-b)-pyridine, m.p., 4951C.

l-ethoxy-6-chloro-2-(trifluoromethyl)-1H- imidazo(4,5-b)pyridine, n 1.5082.

1-( methylcarbamoyloxy )-6-chloro-2- (trifluoromethyl 1 H-imidazo(4,5 -b )pyridine m.p., 267C.

1-( 2-methoxy-3 ,-dichlorobenzoyloxy )-6-chloro-2- (trifluoromethyl)-1H-imidazo(4,5-b)pyridine, m.p., l489C.

1-ethoxy-2,6-bis(trif1uoromethyl)-1H-imidazo(4,5-

b)pyridine, n 1.5100.

l-methoxy-6-nitro-2-(trifluoromethyl )-l H- imidaz( 4,5-b )-pyridine.

l-n-octyloxy-6-(meth ylsulfonyl )-2-( heptafluoro-npropyl l H-imidazo(4,5 -b )pyridine.

i-n-butoxy-6-fluoro-2-( l 1-difluoroethyl)-l H- imidazo( 4,5 -b )-pyridine.

1-phenethoxy-2,6-bis(chlorodifluoromethyl l H- imidazo( 4,5-b) -pyridine.

l-vinyloxy-2,6-bis( difluoromethyl l H-imidazo( 4,5

b )pyridine.

l dimethylcarbamoyloxy )-6-bromo-2-( perfluoro-nhexyl )-l H-imidazo( 4,5-b )pyridine.

l-methacryloyloxy-6-chloro-2-(trifl uoromethyl l H- imidazo- (4,5 -b )pyridine.

l-lauroyloxy-Z ,6-bis(trifluor0methyl)-1H- imidazo(4,5 -b )pyridine.

1-( 2,4-dichlorophenoxyacetoxy )-6-chloro- 2- (trifluoromethyl)-1H-imidazo(4 ,5 -b )pyridine.

l-benzoyloxy-2,6-bis( trifl uoromethyl l H- imidazo( 4,5-b )pyridine.

1-(phenylacetoxy)-6-chloro-2-(trifiuoromethyl 1 H- imidazo-( 4,5 -b )pyridine.

1-(3-phenylpropionyloxy)-6-(methylsulfonyl)-1H- imidazo -(4,5 -b )pyridine.

l-cinnamoyloxy-6-chloro-2-(trifluoromethyl )-l H- imidazo( 4,5-b )-pyridine.

1-( 3-( 2,4,5 -trichlorophenoxy )propionyloxy )-6- chloro-2-(trifluoromethyl l H-imidazo(4,5 b )pyridine.

l-cyclohexyloxy-6-chloro-2-(trifluoromethyl l H- imidazo-( 4,5-b )pyridine.

1-( phenylsulfonyloxy )-2 ,6-bis(difluoromethyl l H- imidaz0( 4,5-b )-pyridine.

l-( benzylsulfonyloxy )-6-chloro-2-( difluoromethyl lH-imidazo- 4,5b )pyridine.

l-( cyclohexylsulfonyloxy )-6-nitro-2- (trifluoromethyl l H-imidazo(4,5-b )pyridine.

1-( p-chlorophenyl )sulfonyloxy )-6-chloro-2- (trifluoromethyl l H-imidazo( 4,5 -b )pyridine.

1-( 2-butenyloxy)-6-(isopropylsulfonyl )-2-( l ,1- difluoro-3-chloropropyl l H-imidazo( 4,5- b )pyridine.

l-( o-octenyloxy )-6-chloro-2-( trifl uoromethyl )-l H- imidazo-( 4,5-b)pyridine.

l-( 9-hexadecenoyloxy )-6-chloro-2- (trifluoromethyl l H-imidazo-(4,5-b )pyridine.

l-( isopropylthiocarbamoyloxy )-6-chloro-2- (pentafl uoroethyl 1 l-l-imidazo( 4,5 -b )pyridine.

l-( 3-amino-2 ,5 -dichlorobenzoyloxy )-6-chloro-2- (trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

l-( 2,5-dichloro-3-nitr0benzoyloxy )-6-chloro-2- (trifluoromethyl l H-imidazo( 4,5 -b )pyridine.

1-( 2-( 4-chloro-o-tolyloxy )acetoxy 2 ,6-

bis(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.

l-( tetrahydro-2-pyranyloxy )-6-chloro-2- (trifluoromethyl l l-l-imidazo( 4,5 -b )pyridine.

1-methoxy-2,6-bis(trifluoromethyl)- l H-imidazo( 4,5-

b )pyridine.

1-( methylcarbamoyloxy )-2,6-bis( trifluoromethyl lH-imidazo-( 4,5-b )pyridine.

l-( 2-methoxy-3 ,6-dichlorobenzoyloxy )-6 amino-2- (trifluoromethyl )-l H-imidazo( 4,5-b )pyridine.

l-( methylsulfonyloxy )-6-nitro-5,7-dibromo-2- (trifluoromethyl l H-imidazo(4,5-b )pyridine.

l-( 2-(4-chloro-o-tolyloxy )acetoxy )--chloro-2- (trifluoromethyl l H-imidazo(4,5-b )pyridine.

1-( 2,4-dichlorophenoxyacetoxy )-7-chloro-2- (trifluoromethyl l H-imidazo(4,5-b)pyridine. 1-methoxy-S-(methylsulfonyl )-2-( pentafluoroethyl lH-imidazo-( 4,5-b)pyridine.

l-ethoxy7-fluoro-2-(difluoromethyl l H- imidazo(4,5-b)pyridine.

l-propionyloxy-5-chloro-6bromo-2-( 1,1 ,2,2-

tetrafluoroethyl l H-imidazo (4,5-b )pyridine. l-octanoyloxy-7-amino-Z-(difluorochloromethyl lH-imidazo( 4,5-b )-pyridine.

l-methoxy-7-nitro-2-(difluorochloromethyl l H- imidazo(4,5-b)-pyridine. l-allyloxy-2.7-bis(trifluoromethyl l H-imidazo(4,5-

b)Py dine l-cyclohexyloxy-S ,6,7-trinitro-2-( trifluoromethyl 1H-imidazo-(4,5-b)pyridine.

l-benzyloxy-5,6,'7-trichioro-2-( difluoromethyl l H- imidazo(4,5-b)-pyridine.

l-phenethoxy-S ,6-bis(diiluoromethyl )-2- (trifluoromethyl l H-imidazo( 4,5-b )pyridine.

l-acetoxy-2,5 ,6-tris( trifluoromethyl )-I H- imidazo(4,5-b)pyridine.

l-acryloyloxy-S ,6-bis(difiuorochloromethyl l H- imidazo(4,5-b)-pyridine. l-(tetrahydro-2pyranyloxy)-5 ,6-bis( ethylsulfonyl 2-( trifluoromethyl l H-imidazo(4,5-b )pyridine. 1-benzoyloxy-6-methyl-2-( trifluoromethyl l H- imidazo(4,5-b)pyridine. 1-methoxy-6-(perfluorooctyl)-2-(trifluoromethyl)- l H-imidazo(4,5-b )-pyridine.

The compounds of the present invention are adapted to be employed as herbicides. The compounds can be utilized to achieve broad herbicidal action; hence, in its broadest sense, the present invention is directed to a method which comprises applying to a plant part, which can be a stern, leaf, flower, fruit, root, or seed or other similar reproductive unit of a plant, a growthinhibiting amount of one of the compounds of the present invention. However, the compounds can also be utilized to take advantage of selective patterns of herbicidal activity.

It is not critical to the practice of the present invention that complete destruction of undesirable vegetation be obtained, it being adequate if the growth of the unwanted vegetation is merely inhibited. Especially where selective action is sought, inhibition falling short of actual killing is adequate, particularly when combined with naturally occurring conditions such as limited moisture and the like which more adversely affect the vegetation selectively inhibited than the crop plant.

The compounds of the present invention are suited to a wide variety of herbicidal applications. Thus, for example, at rates which evoke the selective action of the compounds, which rates are defined more completely hereinbelow, the compounds can be used as selective herbicides in crop plants, such as, for example, cotton, corn, sorghum, soybeans, and the like. in such use, application can be made preemergent to both crops and weeds, or, preferably by means of a directed spray application technique, postemergent to the crop plant but both preemergent and post-emergent to the weeds. in another application, the compounds can be used to give broad herbicidal action on non-crop land, including intermittently non-crop strips of contour-farmed land. For such usage on so-calied fallow land, application can be made in spring to suppress vegatative growth until a fall or following spring planting, or in the fall to suppress vegetative growth until a spring or following fall planting. Furthermore, in another application, the present compounds can be utilized to control weeds in tree crop plantings, such as plantings of the various citrus trees. In all of these various applications, and yet others for which the present compounds are suited, another advantage is that the compounds need not be disced into the soil being treated, it being adequate if one of the compounds, or a formulation containing one of the compounds, is merely spread onto the top surface. However, where desired or convenient, the compounds can be disced into, or otherwise mechanically mixed with the soil. In addition to the foregoing terrestrial embodiments, the present compounds can also be utilized as aquatic herbicides.

The practice of the present invention in any of its numerous embodiments can in some instances be carried out with unmodified compound; however, for good results, it is generally necessary that the compound be employed in modified form, that is, as one component of a composition formulated to implement the plant growth-inhibiting effects. Thus, for example, the active agent can be mixed with water or other liquid or liquids, preferably aided by the usage of a surface active agent. The active agent can also be incorporated on a finely divided solid, which can be a surface active substance, to yield a wettable powder, which can subsequently be dispersed in water or other liquid, or incorporated as part of a dust which can be applied directly. Other methods of formulations are known in the art and can be employed in implementing the present invention.

In carrying out the novel method of the present invention, the exact amount of the active agent employed is not critical and will vary, depending upon the type of growth-inhibiting effect desired, the identity of the plants concerned, the particular active agent used, weather conditions, and the like. In general, a broad growth-inhibiting effect is obtained with rates of from 3-5 to 20 pounds or more of active agent per acre, and such rates are suitable and effective for control of vegetative growth on fallow land. When it is desired to obtain a selective growth-inhibiting effect on weeds in areas containing crop plants such as corn, soybeans, and cotton, rates of from 0.25 or less to 5 pounds generally give good results. When in the typical mode of operation, the active agent is employed as a composition comprising the agent, the exact concentration of active agent in the composition is not critical, except that the concentration and total amount of formulation employed be adequate to supply the appropriate amount of active agent on a per acre basis. In general, good results are obtained when employing formulations containing the active agent in a concentration of from 0.5 to percent or higher, in the instance of a liquid formulation; and in a concentration of from 1.0 to 5.0 percent or higher, in the instance of a dust, powder, granule, or the like. More concentrated formulations can be prepared and are often preferred in that they can serve, depending upon the particular application contemplated and the particular concentration, both as a concentrated formulation for purposes of shipment, storage, and the like, and as an ultimate treating composition. Thus, for example, formulations often preferably contain a surface active agent and the present active agent, the latter being present in an amount of from 0.5 to 99.5 percent, by weight; or an inert, finely divided solid and the present active agent, the latter being present in an amount of from 1.0 to 99.0 percent, by weight. Such formulations, as indicated, can be employed directly in certain applications, but can also be diluted and subsequently employed in many other applications.

Liquid compositions containing the desired amount of active agent are prepared by dissolving the substance in a liquid with or without the aid of a surface active dispersing agent such as an ionic or non-ionic emulsifying agent. Most preferably, the subject compound is dissolved in water or in an organic liquid carrier, aided by the use of a surface active dispersing agent. Suitable such organic liquid carriers include agricultural spray oils and the petroleum distillates such as diesel fuel, kerosene, fuel oil naphthas and Stoddard solvent. The choice of dispersing and emulsifying agent and the amount thereof employed is dictated by the nature of the composition and by the ability of the agent to facilitate the dispersion of the active agent in the carrier to produce the desired composition. Dispersing and emulsifying agents which can be employed in the compositions include the condensation products of alkylene oxides with phenols and organic acids, alkyl aryl sulfonates, polyoxyalkylene derivatives or sorbitan esters, complex ether alcohols, and the like. Representative surface active agents which are suitably employed in implementing the present invention are identified in US. Pat. Nos. 3,095,299, second column, lines 25-36, 2,655,447, column 5, and 2,412,510, columns 4 and 5.

In the preparation of dust compositions, the active ingredient is intimately dispersed in and on a finely divided solid such as clay, talc, chalk, gypsum, limestone, vermiculite fines, perlite, and the like. In one method of achieving such dispersion, the finely divided carrier is mechanically mixed or ground with the active agent.

Similarly, dust compositions containing the toxicant compounds can be prepared with various of the solid surface active dispersing agents such as bentonite, fullers earth, attapulgite and other clays. Depending upon the proportions of ingredients, these dust compositions can be employed as concentrates. and subsequently diluted with additional solid surface active dispersing agents or with chalk, talc, or gypsum and the like to obtain the desired amount of active ingredient in a composition adapted to be employed for the suppression of the growth of the plants. Also, such dust compositions can be dispersed in water, with or without the aid of a dispersing agent, to form spray mixtures.

Formulations containing the present active agent are often advantageously further modified by incorporation therein of an effective amount of a surfactant which facilitates the dispersion and spreading of the formulation of the plant leaf surfaces and the incorporation of the formulation by the plant.

In accordance with the present invention, the active agent can be dispersed in soil or other growth media in any convenient fashion. Applications can be carried out by simply mixing with the media, by applying to the surface of soil and thereafter dragging or discing into the soil to the desired depth, or by employing a liquid carrier to accomplish the penetration and impregnation. The application of spray and dust compositions to the surface of soil, or to plant parts or the above ground surfaces of plants can be carried out by conventional methods, e.g., power dusters, boom and hand sprayers and spray clusters, whether surface or air-borne. However, while such conventional modes of application can be used, they are not required. As above noted, it is an advantage of the present invention that the compounds serving as active agent are active and effective as herbicides when merely placed on the surface of the soil, without any additional step to assist incorporation. Thus, the compounds are of substantially the same efficacy regardless of whether they are applied to the surface only, or whether they are applied to the surface and subsequently disced into the soil.

In a further method, the distribution of the active agent in soil can be accomplished by introducing the agent into the water employed to irrigate the soil. In such procedures, the amount of water is varied with the porosity and water holding capacity of the soil. to obtain a desired depth of distribution of the agent.

In addition, the present method also comprehends the employment of an aerosol composition containing one or more of the present active agents as an active compound. Such a composition is prepared according to conventional methods wherein the agent is dispersed in a solvent, and the resultant dispersion mixed with a propellant in liquid state. Such variables as the particular agent to be used and the nature of the vegetation which is to be treated will determine the desirability of the solvent and concentration of the agent therein.

Satisfactory results are obtained when the active agent of the present invention, or a composition comprising such active agent, is combined with other agricultural materials intended to be applied to plants, plant parts, or their habitats. Such materials include fertilizers, fungicides, nematocides, insecticides, other herbicides, soil conditioning agents, and the like.

The following further examples illustrate the herbicidal utility of the compounds of the present invention.

EXAMPLES 62-70 Various of the compounds of the present invention were evaluated for preemergent application to various crop and weed species. Each compound was formulated by dissolving it in a 1:1 mixture of acetone and ethanol containing a small amount of a blend of sulfonate nonionic emulsifying agents; the solution was then diluted first with deionized water, then serially with deemulsifiers. The resulting solutions contained the subject compound in various amounts, the emulsifier blend in a concentration of 0.1 percent, and the acetone and ethanol each in a concentration of 4.0 percent.

A soil was prepared consisting of one part masonry sand and one part shredded top soil blended together in a cement mixer. One gallon of this soil was placed in a 21.5 X 3 1.5 cm. galvanized flat and was patted down with a bench brush until level. A three-row marker was used to make 2% cm. deep furrows in approximately two-fifths of the flat. Crop seeds consisting of four kernels of corn, five cotton seeds and five soybean seeds were placed in these furrows. A four-row template was then placed on the remaining soil and the indicated approximate numbers of each of the following seeds were planted, one species to each section: foxtail (millet), -l00 seeds; velvetleaf (40-50 seeds); rough pigweed (150 250 seeds); and large crabgrass -150 seeds).

Sufficient soil was added to cover the entire flat. Thus, the weed seeds were covered to a depth of about 6 mm. and the crop seeds were covered to a depth of about 3 cm.

In assaying the effect of the composition as preemergent herbicides, a flat prepared as above, taken either on the day of planting or on the next day, was placed in a chamber equipped with a turntable and an air exhaust. The herbicidal composition was applied to the flat with a modified DeVilbiss atomizer hooked to an air source. Twelve and one-half milliliters of the composition under test were applied to each flat either on the day of planting or on the succeeding day. lnjury ratings and observations as to type of injury were made eleven to twelve days after treatment. The injury rating scale used was as follows:

0no injury lslight injury 2moderate injury 3-severe injury 4death When more than one determination was carried out at a given rate, an average value was calculated for the injury rating.

in the following table setting forth the results of the evaluation, column 1 gives the name of the compound under test; column 2, the rate in pounds per acre at which the compound was applied to the test flat; and the remaining columns, the injury to the particular plant seeds or seedlings as measured by the foregoing ionized water containing 1000 ppm. of the blend of 59 Scale- TABLE I lniurv Rating on Preemereent Treatment LbSJ Velvet- Compound Acre Corn Cotton Soybean Crabgrass Pigweed Foxtail leaf l-Methoxy-6-chloro-2- 8 2 4 3 3 3 4 3 (trifluoromethyl )-1H- imidazo(4.5-b)pyridine 4 2 2 1 4 4 4 4 2 l l i 4 3 4 4 l O l 0 3 3 3 4 l-Acctoxy-6-chloro-2- 8 1 3 2 3 3 (trifluoromethyl )-l H- imidazo(4,5-b)pyridine 4 l (l O 2 2 3 3 2 O O l i 2 3 3 l-Ethoxy-6-chloro-2- 8 3 3 4 4 (trifluoromethyl l H imidazo(4,S-b)pyridine 4 0 0 l 4 3 4 2 O 0 O 3 2 2 l-Allyloxy-6-chloro-2- 8 3 4 4 4 (trifluoromethyl)-1H- imidazo(4,5-b)pyridine 4 l 0 0 4 3 4 TABLE 1- Continued Iniurv Rating on Preemergent Treatment Lbs./ Velvet- Compound Acre Corn Cotton Soybean Crabgrass Pigweed Foxtail leaf l-lsopropoxy--chloro-Z- 8 2 4 4 4 (trifluoromethyl)-1H- imidazo(4,S-b)pyridine 4 l O l 4 2 1 4 2 O 0 O 2 l 3 l-(Allylcarbamoyloxy-6- 8 2 3 3 4 chloro-2-(trifluoromethyl)-l H-imidazo- 4 O l l 3 3 2 (4,5-b)pyridine 2 l 2 l 0 2 l-Octanoyloxy--ehloro- 8 2 3 4 4 2-(trifluoromethyl)-1H- imidazo(4,5-b)pyridine 4 l 4 l 4 2 4 l-(Methylcarbamoyloxy)- 8 3 3 4 6-chloro-2-(trifluoromethyl)-lH-imidazo 4 l 2 l 3 3 4 (4,5-blpyridine 2 O l l l 3 4 l-Methoxy-S-ehloro-Z- 8 3 4 4 4 4 (trifluoromethyl)-ll-limidazo(4,5-b)pyri- 4 2 O 2 3 3 4 4 dine NOTE: Dashes indicate species which were not tested.

EXAMPLES 71-76 25 application. These studies were made with a greater va- Representative compounds of the present invention were evaluated for postemergent application to plants including com and several weed species. The evaluation was carried out in accordance with the procedures of Examples 62-70 except that the test solutions were applied about 9-12 days after the preparation and seeding of the flats. The results are as set forth in the following table:

riety of plant species, at lower rates of application. Formulation of the compounds, however, was carried out in the same manner as described in preceding examples.

Rating of the herbicidal effect was on a scale of 0-10, with 0 indicating no herbicidal effect, and 10 indicating non-emergence or death. In addition, the kind of herbicidal effect was observed and recorded in accordance TABLE II lniurv Rating on Postemergent Treatment Compound Lbs/Acre Corn Crabgrass Pigweed Foxtail Velvetleaf l-Acctoxy6-chloro-2-(tri- 8 4 4 4 4 4 fluoromethyl l H-imidazo- (4.5-b)pyridine 4 4 4 4 4 4 2 4 4 4 4 4 1 2 4 4 4 4 l-Ethoxy-6-chloro-2-(tri- 3 4 4 4 4 4 fluoromethyl)-l l-l-imidazo- (4,5-b)pyridine 4 4 4 4 4 4 2 2 4 4 4 4 l l 4 4 3 4 l-(3,6-Dichloro-2-methoxy- 8 l 4 4 3 3 benzoyloxy)-6-chloro-2-(trifluoromethyl)-l H-imidazo- 4 0 3 2 3 3 (4,5-b)pyridine 1-(Methylcarbamoyloxy)-6- 8 2 4 4 4 4 chloro-2-(trifluoromethyl)- IH-imidazo(4,5-b)pyridine 4 2 4 4 4 3 2 2 4 4 3 4 l l 3.5 4 4 2.5 '6 O 4 3 4 2 '24: 0 4 3 3 2 l-Methoxy-6-amino-5,7-dibromo- 8 0 3 4 3 2 2-(trifluoromethyl)-lH-imidazo- (4,5-b)-pyridine l-(Methylcarbamoyloxy)-6- 8 3 4 4 4 4 EXAMPLES 77-87 Other studies were carried out, evaluating various compounds of the present invention for preemergent with the following notation system:

A Abscission of leaves B Burned C Chlorosis D Death E Epinasty F Formative effects other than epinasty G Dark Green 1 lncreased plant growth L Local necrosis N No germination P Purple pigmentation ditions. The compound was formulated in conventional procedures and applied as a soil surface spray to beds seeded with corn and selected weed species. The evaluations were carried out in a sub-tropical climate; there R Redufied germmatlon 5 having been no rainfall in the first seven days following 5 Stuntms application, /2 inch of sprinkler irrigation was applied. U Unclasslfied m-lury Observations were made periodically for emergence,

TABLE 111 Morn- Coc- Vel Fox- Barn- Lbs./ Cot Soy- Pea- Soying kle vet tail Ragyard Compound acre Corn ton bean Rice nut Corn bean glory bur leaf millet weed grass l-Methoxy6-chloro-2- 0.5 ZSC 0 0 0 0 0 10D 4BC 38C SBC BBC 813C (trifluoromethyll-1H- 1.0 48C 38 SEC 4BC 0 25C 3C8 10D 10D 7BC 9BC 10D )BC imidazo(4,5b)pyridine 2.0 SC 7BC 913C 6BC 3C 45C 8C8 D 10D 10D 10D 10D 9.5BC l-Acetoxy-6-ch1oro-2- 0.5 0 0 0 0 0 0 0 10D 4BC 4BC BBC ZBC (trifluoromethyll-IH- 1.0 45C 6BC SBC 4BC 0 35C 6BC 10D 10D 83C 58C 10D 4BC imidazo(4,5-b)pyridine 2.0 SSC 10D 10D 7BC 3C 68C 98C 10D 10D 9BC 9.5BC 100 8.5 BC 1-EthoXy-6-Chloro-2 0.5 0 0 0 0 0 0 0 28C 0 0 0 BBC 0 (trifluoromethyl)-IH- 1.0 0 0 0 0 0 0 0 101) 0 7BC 88C 10D BBC imidazo(4.5-b)pyn'dine 2.0 25C 0 6BC 53C 0 35C 93C 10D 10D 9BC 10D 10D 913C l-Benzyloxy-6-chloro-2- 0.5 0 0 0 0 0 0 0 0 0 0 0 4BC 0 (trifluoromethyD-IH- 1.0 0 0 0 0 0 0 0 25C SSC 3BC 4BC imidazo(4,5b)pyl'idine 2.0 0 0 0 0 0 0 0 SEC 0 38C 35B BBC 4BC 1-Allyloxy-6-chl0ro-2- 0.5 0 0 0 0 0 0 0 98C 0 4BC 0 6BC 313C (trifluoromethyh-lH- 1.0 0 0 0 0 0 O 0 10D 0 BBC 7BC 98C 8BC imidazo(4.5-b)pyridine 2.0 0 0 0 3BC 0 0 4BC 10D 5 BC SBC 9.5BC 9BC 9BC 1-lsopropoxy-6-chloro-2- 0.5 0 0 0 0 0 0 0 88C 2C ZBC 0 6BC 0 (trifluoronrethyD-IH- 1.0 0 0 0 0 0 0 0 100 2C ZBC 25 98C 48C ilnidazo(4,5blpyridine 2.0 ZSC 0 0 0 0 0 0 10D 6BC 858C 9.5BC 98C 1(Al1ylcarbamoyloxy-fi-chloro-Z- 0.5 0 0 0 0 V 0 O 0 813C 4BC 0 2 6BC 0 (trifluoromethyl)-1H- 1.0 O 0 0 28C 0 0 0 10D 10D 213C .4BC SBC 6BC imidazo(4.5-blpyrldine 2.0 0 SEC SBC 6BC 2C 25C 58C 10D 10D SBC 8BC 10D BBC l-(Octanoyloxy-6chloro-2- 0.5 0 0 0 0 0 0 0 7BC 0 0 SBC 0 (triflu0romethyl)-1H 1.0 0 3C SEC 358 0 0 2C 10D 4BC 4B5 9BC 6BC imidazo(4.5-b)pyridine 2.0 38C 7BC 7BC 513C 0 45C 7BC 10D 10!) 98C 8BC 9.5BC 7BC 1-(2-Methoxy-3,6-dichloro-benzoyloxy)- 0.5 0 BF 7F 6F 6F 0 8F 7F 10D 2F 25 8F SFS 6-ch1oro2-(trifluoromethyl)-1 l-l- 1.0 28 5F 10D 8F 10D 0 10D 8F 8F 35F 10D 4FS imidazo(4.5-b)pyridine 2.0 45 9F 10D 9F 9F 10D 10D 10D 10D 45F 10D SFS 1-(Methylcarbamoyloxy)-6 chloro2- 0.5 0 0 0 0 0 0 0 10D 4BC ZBC 98C 58C (trifluoromethyD-lH-imidazo 1.0 C C 4BC 4BC 0 15C 38C 10D 10D 7BC BBC 10D 4BC (4.5-blpyridine 2.0 C 8BC 10D 6BC 0 SSC 10D 10D 10D 10D 10D 10D 10D 1-Ethoxy-2,6bis(trifluoromethyl) 0.5 0 0 0 0 0 0 0 7BC 0 0 0 0 1H-imidazo(4.5b)pyridine 1.0 0 0 0 0 0 0 0 10D ZBC 0 7BC 25 2.0 35C 28C 4BC 213C 0 C BBC 10D 10D 4BC 98C 98C 35 Control 0 0 0 0 0 0 0 0 0 0 0 0 0 Control 0 0 0 0 0 0 0 0 0 0 0 0 0 EXAMPLE 88 1 -Methoxy-6-chloro-2-( trifluoromethyl l H- imidazo-(4,5-b)pyridine was evaluated under field concorn injury, and weed control. The results were as ex- 0 pressed in the following table, with date of observation expressed as the number of days from the day of seed ing and compound application.

TABLE IV A Percent Weed Control Emergence" Crop lniury All Observations Day 17 Rate Prick- Common Morn- Fox- Black (LbsJ Day Day Day Day Day Day ly Venice pursingtail night- Pig- Compound Acre) 5 7 1 1 l 1 17 38 sida mallow lane glory millet shade weed l-methoxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine 4 96 85 83 2.0 3.7 4.3 100 100 100 100 100 100 100 Control 0 100 100 100 0.0 0.0 0.0 0 0 0 0 O 0 0 Emergence expressed as a percent of the control.

Number of emerged corn seedlings per 15 feet of row. "Crop injury on a 0-10 scale where 0 no injury. 1-3 slight. 4-6 moderate, 7-9 severe, and 10 death of all plants.

"Needs/51.1.t'l. based on 5 one sq. ft. counts per plot.

As noted above, the compounds of the present invention can be used in conjunction with other agricultural materials, including other herbicides. Thus, in one em bodiment, the present invention is directed to a method which comprises applying essentially simultaneously to a plant part an amount of a first substance which is:

1-methoxy-6-chloro-2-trifluoromethyl-l1-1- imidazo(4,5-b)-pyridine, 1 -methoxy--chloro-2-trifluoromethyl-1H- imidazo(4,5-b)-pyridine, or l-methoxy-2,6-bis(trifluoromethyl)- l H-imidazo(4,5-

b)-pyridine; and an amount of a second substance which is:

alachlor,

atrazine,

butylate,

2-chloro-4-( 1 -cyano- 1 -methylethylamino)-6- ethylamino-s-triazine,

dalapon,

dinoseb,

diuron,

EPTC,

linuron,

oryzalin,

propachlor,

propazine,

simazine,

trifiuralin, or

TCA, the amounts being such as to effect, in combination, growth inhibition. This embodiment of the present invention also comprehends a combination of the first and second substances, which combination is useful in implementing the method.

The substances serving as the second substance of the present herbicidal methods and combinations are in every instance known compounds. For a convenient compilation of information and references on these and other known herbicides, attention is directed to the Herbicide Handbook of the Weed Society of America, sec. ed., published by The W. F. Humphrey Press, Inc, Geneva, New York, 1970, and available from Weed Science Society of America, Department of Agronomy, University of Illinois, Urbana, Illinois 61801.

The known herbicides serving as the second substance are generally crystalline solids, typically white in color; the exceptions are butylate (an amber liquid); EPTC (a light yellow-colored liquid); and dinoseb (which may exist as either a dark brown solid or a dark orange liquid, depending on temperature). Each of these compounds is individually effective at a range of rates, depending upon the particular substance, the particular use (for example, whether a selective or general herbicidal effect is sought), and the type of soil and other growing conditions. The generally established rate ranges for these known herbicides, when used individually, are as follows:

Established Rate Z-chloro-4-( l-cyano l -mcthylcthylumino)-6-ethylaniinos-trinzine dalapon dinoscb TC A 4-30 (selective) 50-200 (general) (Herbicide Handbook of the Weed Society of America, supra)v 1n employing these known herbicides in combination with the herbicides of the present invention, the precise ratio of the herbicidal agents to one another-is not critical. It is generally preferred that the known herbicide be used in an amount within its established rate range for individual use as sole herbicidal agent, although because of the herbicidal effect attributable to the ether, lesser amounts within the established rate range or amounts below the established rate range are appropriate. Thus, amounts below the median of the established rate range generally give good results in combination with the specified ethers. However, each of the ether and known herbicide components should be employed in an amount which, if employed individually as sole herbicidal agent, would exert at least a minimal plantgrowth inhibiting effect. In the case of alachlor, atrazine, and propachlor, for example, the established rate ranges are 1-4 lbs/acre of alachlor, 2-4 lbs/acre of atrazine, or 3-6 lbs/acre of propachlor; but good results generally are obtained in the present combinations at application rates of 2.5 lbs/acre or less of alachlor, 3 lbs/acre or less of atrazine, or 4.5 lbs/acre or less of propachlor. For the specified ethers serving as the first component, application rates of 025-4 lbs/acre are desirable for selective activity, and preferred rates for selective activity are generally l2.5 lbs/acre.

The substances can be administered separately, although preferably essentially simultaneously, and this mode of administration is sometimes preferred. Thus, for example, different herbicides may require different modes of application which preclude a single application. In particular, each of butylate and EPTC is preferably applied to corn prior to planting and with mechanical mixing into the soil. The ethers of the present invention are preferably applied to corn immediately after seeding but without mechanical mixing. Thus, separate administration is sometimes preferred in order to make best utilization of the respective herbicidal properties. Where separate administration is preferred, the exact interval between applications is not critical; but optimal results generally are obtained when the respective administrations are essentially simultaneously, such as within several minutes to not more than within several hours of one another. The time interval between applications is largely dictated by the practicalities of agricultural practices.

Generally, however, it is preferred that both substances be formulated as a single formulation. The formulation is conducted in accordance with conventional procedures, utilizing such adjuvants as surface-active agents, inert finely-divided solids, and the like. Reference is made to the discussion hereinabove concerning formulation of the compounds of the present invention, generally. Where the objective is selective herbicidal activity, it is generally preferred that the specified ether comprise at least 40 percent by weight of the total herbicidaIly-active component.

EXAMPLES 89-103 I -Methoxy-6-chloro-2-trifluoromethyl- I H- imidazo(4,5-b)-pyridine was evaluated in combination TABLE V COMBINATION OF IMETHOXY-6CHLORO-Z-TRIFLUOROMETHYL-IHIMIDAZO(4.5-bIPYRIDINE (AW WITH ALACHLOR ("B") Morn Barn- Large John- Com Rates ing Foxtail Ragyard crab- Pig- Sor- Velvet Iimson son Lambs pounds Lbs/Acre Glory Corn millet weed grass grass weed ghum Rice leaf Corn weed grass quarter A+B 0.25 0.5 IOD O IOD 95B ION 9.5RS 9.5RS 35B 95R 45B 65B 58 95 do. do. I IOD O IOD 95R ION 9.9RS ION 55B ION 788 O IOD IOD ION do. do. 2 IOD 1S IOD 9.5RS ION ION ION 95F ION 988 O 985 IOD ION do. do. 4 IOD 2S ION IOD ION ION ION 85F ION 9B5 9B8 IOD ION do. 0.5 +0.5 IOD O IOD IOD ION 9.5RS 9.5RS B 85 8513 IS 8B8 9B5 ION do. do. I IOD O ION IOD ION IOD 9.5RS 4BSF 8R5 835R O 885 9.585 ION do. do. 2 IOD 3S IOD 9.5BSR ION ION IOD 85F ION 9B5 O 985 9.5BS 9R5 do. do. 4 IOD 3S ION ION ION ION ION 9FSR 9.8RS 9.585 25 9.585 ION ION do. I +0.5 IOD 2SB IOD IOD ION 9.5BS 9.5RS 7B5 SBSR 985 O 988 7B5 9R5 do. do. I IOD IS IOD IOD ION 9.8RS 9.8RS 8B5 9R5 IOD 35 988 IOD ION do. do. 2 IOD 3S ION 9.8RSB ION 9.8RS ION 8BSF 9.5RS IOD O 9.5BS IOD ION do. do. 4 IOD 3S IOD 9.5BSR ION IOD ION 9BSF 9.5RS 95B 25 9.555 IOD ION do. 2 +0.5 IOD 3S IOD 8S ION 9.8RS 9.5RS 9.585 788 IOD 35 9.585 988 9.8RS do. do. I IOD IS IOD 9.5RS ION ION 9.8RS 9 9R5 888 IS 9.885 985 ION do. 2 +2 IOD O IOD 9.8RS ION ION ION 9B5 IOD 9.585 158 9.585 IOD ION do. do. 4 IOD 3S IOD IOD ION ION ION 9.5BSF ION 9585 458 9.885 IOD ION Control 0 O 0 O O O O O O O O O O O O TABLE VI COMBINATION OF IMETI'IOXY-6-CHLORO-Z-TRIIFLUOROMETHYL 1HIMlDAZO(4.5b)PYRIDINE (ii") WITH ATRAZINE (B) Rates Morn- Pig- Rag- Corn Velvet Lambs .Iimson Barn Rice Large Corn Fox- Sor- John- Com- Lbs./ ing weed weed Leaf Quar- Weed yard Crabtail ghum son pounds Acre Glory ter Grass grass Millet Grass A+B A A BSD 9R5 8R5 O 335 7R5 8.581) 5B8 2B5 48 O 38 0 25 do. A i IOD 9.5RS 8RSD O 538 7RSD 95D 88D 3B5 O 4B5 O S do. A I 9.5SD ION 8RSD O 'ISD 7R5 98D 9.5SD 38S O 438 O 385 do. A 2 IOD 9.5RS 9.5RSD O 9.5SD 'IRS 9.5SD 9.5SD 3B8 0 75D O 485 do. V2 V4 IOD 9.5RS 6.5SD O 7SD 7.5RS 98D 3B8 7R5 O 88D 0 488 do. A A IOD 9R5 95D 0 75D 5R5 9.551) 9.5SD 4B8 7R5 O 75D O 75D I TABLE XVIII COMBINATION OF I M IH-IMIDAZO(4.5-b)P Rates Morn- Fox- Barn- Large John- Com- LbsJ ing taiI Ragyard Crab- Pig Sor- Velvet .IImSOI'I son Lambs pounds Acre GIory Corn Millet weed Grass grass weed ghum Rice Lcuf Corn Weed brass Quarter A+B 0.21 0.25 683 88R 58 9R8 ION ION 85R 55C (I (I 25 SS R do. do. 0.5 888 O 95R D 9R5 9.5 ION 'ISR 65C 358 O SSH 4h 55 RS do. do. 10 IOD 0 )BSR IOD QRSB 9.5 9.5 95R SSCB NBS M18 LSRS QIISR RS BS do. do. 2.0 IOD 5S ION IOD 9.5 9.5 ION IISR 558 I01) )BSR ION ION R8 R5 do. 0.42 0.25 SSB 4S QRSB B ION ION ION ION 88C 25 45C 25( R do. do. 0.5 6B5 53 9.8 IOD 9.5 9.5 ION ION )SC 35 4S SSB ION HSR RS RS RS do. do. I.O IOD 45 9.8 IOD ION ION ION 9.8 BSC IOD 55B 985 9R5 RS R5 R5 do. do. 2.0 IOD 5S ION IOD ION ION ION ION 8SCR IOD SSC )BS 9.5RS ION do. 0.83 0.25 658 'IFSC ION 7R5 9.5RS ION ION ION )CSR 3S 7CSF 33 9.5 R5 8R5 do. do. 0.5 755 BRSF ION IOD .,ION ION ION 9.9RS QCSR 45B TCSF 8BSF .888 9.5RS do. do. L0 853 SBSF 9.8 IOD 9.8 ION ION ION QSRF 738 5C 9.5 9.5RS

RS R WW, L do. '68." "'20 988 BSCB ION 10D ION 10w ION ION scn 9.835 7503 QBSF ION 9.511s do. 2.0 0.25 758 )RSF ION EBSRIQI ION 10w ION 9.5531 QRSF 45B ION ION do do 0 5 B 9R5}; ION 0.5 BS ION ION ION ION 9.8 SSF SFSB 65F ION ION RS d0. 20 1.0 IOD )FSB ION IOD ION ION R ION 9R5 IOD )SF ION do. do. 2.0 IOD QFSB ION IOD ION ION 9.5 ION 9.5 9.5 QFSB IOD ION ION RS SR BS Con- 0 O O O 0 O O 0 O 0 O U 0 0 0 no] TABLE XIX COMBINATION OF I-METHOXY-6CI-ILORO2-TRIFLUOROMETHYL- IH-IMIDAZO(4,S-b)PYRIDINE (A) WITH TCA PB) Rates Morn- VeI- Lambs Jim- Barn- Large Fox- John- Com- Lbs./ ing Pig- Rag- Corn vet Quarson yard Rice Crab- Corn mil Sorson pounds Acre Glory weed weed leaf ter Weed Grass grass MiIIet ghum Grass A+B Y4 2CS IS 0 O 2.55 IS 0 IS 0 4BFD 0 385 do. V4 1% 2C5 2S 0 25 4S O 5135 85D 0 'I'BFD O 388 do. 5 3 ZCS IS 0 3R5 25 2S 9BSD JBSD O QBFD O 485 do. A 6 IC IS O 35 3S 7BFS IOD 7850 O 9.5 'IBFD SBSD BFD do. 1% BBS O 0 2S 'IBSD 3S GBSD 53$ 0 8.5 O 485 BSD do. we 1V2 SBS O 4C5 35 688B 485 585 385 O 785i) 0 SBSD do. A 3 4BSD O SCBS 8R8 IOD 835D BBS SSD O 'IBFSD 3BFS QBSD do. /2 6 738B 3FS 6BSD SRSD 985D 688D 888D 7BSD ZFS 93D 8BFSD 9851) 8 do. 1 =54 9BSD 0 738B ms QBSD 7BSD 313s 685B is 8550 0 BBSD do. I IV; 985D O SBS 7R5 9.5 )BSD 8.5 JBSD 1.55 9BSD BBS )BSD BSD BSD do. 3 SCBS O (ICES 4R8 )BSD fiBSD 'I'BSD )BSD 2S IOD 38S XBSI) do. I t 6 IS XBSD 8R5 IBSD 935D JBSD )BS[) 0 3.5 MIFS IUI) BCSD IISI) do. 2 IOI) 2S 9880 7R5 0.5 0.5 MISI) 8831) IS IIISII HIS )IISU BSD BSIJ do. 2 W1 IOD IS QBSD 7R5 9.5 9.5 6350 988B 25 :01) ms was!) BSD BSD do. 2 3 10D 35 985B 8R8 QBSD 9.5 7880 SBSD 0 IOD 685D 9.55s!) BSD do. 2 6 IOD 4FS IOD 9R5 QBSD QBSD 8.5 3P5 IOD 8.5 IOD BSD BSFD Con- 0 O 0 0 O O O O O O O 0 troI EXAMPLES 104-107 imidazo(4,5-b)pyridine and with I-meth0xy-2,6-

with

bis( trifluoromethyl I H-imidazo(4,5-b )pyridine. Each was employed in combination with aIachIor and separately in combination with atrazine. The results were as set forth in the foIIowing tables.

TABLE XXII Continued Rates Morn- Corn Fox- Rag- Barn- Large Pig- Sor- Rice Velvet Corn Iimson .Iohn- Lambs Com- Lbs./ ing tail weed yard Crab weed ghum Leaf Weed Quarson pounds Acre Glory Millet Grass grass Grass ter do. do. 21) 9.5 lS 10D ION 10o ION lON SBSF 9.5 935 IS 988 9.5 ION BS RS BS do. do. 4.0 9.5 35 IOD 10D IUD IUD IUD 9.5 MW )IlS 4SI IUD 9.5 ItIN BS BS US do. 1.0 +0.5 9.5 II HID (IS 73R RRSII IUI) 43F" 45 JIIH ll HIS NUS IRS BS do. do. I.() BBS (I IOD 7R5 9R5 IRSII Illl) XIISI' RS HIS II J N I R H IIS IIS RS do. do. 2.0 9.5 35B ION 8R5 IOD IUD ION IIRSB 9.5 35 9.5 Q 9.5

ION BS B5 B5 R5 R5 do. do. 4.0 ION 0 ION 95R ION ION D 9.5 ION 9B5 35 9B5 IUD 9.5 RS RS do. 2.0 +0.5 IOD 0 IOD 8B5 9R5 8B5 QBSR 8BS BRS 9.535 9B8 9BSR 9.5 RS do. do. 1.0 10D 38 10D 73 9.5 9.5 IOD 8B5 9R5 985 I53 9.5 9.5 9.5 RSB BS BS BS RS do. do. +2.0 IOD 3S IOD 85R 9.5 IOD 10D 9BSF 9.5 9.5 45 9.5 10D ION 85 RS BS BS do. do. 4.0 IOD B ION IOD ION ION ION QBSF 9.5RS 9.585 35 9.585 IOD ION Con- 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 trol TABLE XXIII COMBINATION OF l-METHOXY-2,6-BIS(TRIFLUOROMETHYL) IH-IMIDAZO(4,5-b)PYRIDINE (A") ATRAZINE (B") Rates Morn- Corn Fox- Rag- Barn- Large Pig Sor- Rice Velvet Corn Jimson Iohn Lambs Com- Lbs./ ing tail weed yard Crab weed ghum Leaf Weed son Quarpounds Acre Glory Millet Grass grass Grass ter A+B 0.25 +0.25 3B5 0 3B 25 0 28 58B 0 2B 28 0 2B 0 783 do. do. 0.5 585 0 4B BBS 4S E 6B5 0 38 45B 25 835 O 8B5 do. do. I.0 10D 0 785 BBS 35B 48B 8B5 IE 78 IOD 0 985 IE 885 do. do. 2.0 10D 0 985 10D BBS 6B5 885 0 8B IOD 0 IOD 2B 785 do. 0.5 +0.25 9B5 0 3B 435 3SB 635 758 0 5B 45B 25 835 0 658 do. do. 0.5 985 0 4B 68 45 4S E 0 68 55B 0 IOD 28 788 do. do. 1.0 IOD 0 585 10D 45B SSB 785 0 7B 985 O IOD 0 758 do. do. 2.0 8B5 4S8 SBS IOD 7B5 7E8 858 0 5B IOD 0 9B5 ZS 785 do. I.0 +0.25 9.5135 0 785 4S8 45 SSE 35B 0 0 885 0 9B5 25 8B5 do. do. 05 IOD 0 78s B 45 58B 858 IR 385 9.585 0 9B5 25 885 do. do. 1.0 9.585 0 7B8 888 SS3 SSB 835 IE 55 IOD IS 9.585 IS 958 do. do. 2.0 IOD 0 9.535 958 8B8 8B5 885 353 8B 9535 0 9.5BS 25B 9B5 do. 2.0 +0.25 9.58s 0 SBS BBS 5S3 BBS 888 4B 5B 938 0 935 388 BBS do. do. 0.5 IOD 0 BBS 9B5 4B 688 853 3B5 58 9B5 25 9135 485 985 A-I-B 2.0 +1.0 IOD O BBS IOD SSB 7E8 858 2B 7B IOD 2S IOD 45B 8B5 do. do. 2.0 IOD 0 885 IOD 8B8 735 858 5B 7B 10D 35 IOD 4B 9135 con- O 0 O O 0 0 0 0 0 0 0 0 0 0 0 trol EXAMPLES 108-] I0 soil surface immediately after planting with corn. Prior l-Methoxy-o-chloro-2-trifluoromethyll H- imidazo(4,S-b)-pyridine was evaluated separately in combination with each of alachlor, atrazine, and propachlor. The evaluations were conducted under field conditions at a location in the southern coastal plain. The compounds were formulated by tank-mixing a commercial application of the respective known herbicide with an emulsifiable concentrate of the l-methoxy-6- chloro-Z-trifluo'romethyl- I H-imidazo( 4,5-b )-pyridine. The tank-mixed formulation was then applied to the TABLE XXIV COMBINATION OF I-METHOXY-6-CHLORO-2-TRIFLUOROMETHYL-lI-I-IMIDAZOMj-MPYRIDINE (A"l WITH ALACI-ILOR ("B). ATRAZINE (C), AND PROPACHLOR PD") Percent Rate in Reduction in Corn Percent Weed Control Treatment Lbs/Acre Emergence lniury Foxtail Millet Sickleood (10 Days) 23 64 I6 24 42 I6 24 42 Days Days Days Days Days Days Days Days A 1.0 0 0 3 61 88 90 l4 l4 COMBINATION OF l-METHOXY-G-CHLORO-Z-TRIFLUOROMETHYL-lH-lMlDAZO(4.5-b)PYRlDINE (A") WITH ALACHLOR ("B"), ATRAZINE (C"), AND PROPACHLOR (D") Percent Rate in Reduction in Corn Percent Weed Control Treatment Lbs/Acre Emergence Iniurv Foxtail Millet Sicklepod Days) 23 64 16 24 42 16 24 42 Days Days Days Days Days Days Days Days do. L 0 0 O 33 92 98 14 0 do. 2.0 9 13 17 I1 I00 I00 0 0 do. 3.0 17 23 56 I00 100 0 O B 2.0 3 0 0 67 62 97 0 0 No A+B 0.75+0.75 0 O 0 89 83 95 l4 0 Readdo. O.75+l .0 2 O 0 I00 96 98 I4 57 ing do. L0 +l.0 O 0 0 100 96 I00 0 0 Made 4 1 n 41.5 0 0 o 94 100 100 14 7! do. l.5 +2.0 (7 0 0 I00 100 I00 29 0 C 2 4 0 7 l l 33 88 O 57 A+C O.75-H).75 0 O 0 44 79 97 0 14 do. 0.75+l 0 O 3 44 79 98 0 l4 do. 1 +1 0 0 0 72 96 I00 29 43 do. 1 +1.5 0 0 0 61 96 I00 57 86 No do. 1.5 +2 0 0 7 50 I00 I00 43 86 Read- D 5 0 O O 72 I00 95 14 0 ing A+D O 75+2 l0 0 7 I00 92 97 O 0 Made do. 0 75+3 O O 0 I00 100 I00 I4 29 do. 1 +2 0 O 0 I00 96 100 29 29 do. I +3 0 O 0 I00 I00 I00 14 0 do. I +5 13 O 0 I00 100 I00 29 O The compounds of the present invention can also be employed as the starting materials in a reaction to prepare yet other compounds useful as herbicides. In general, this reaction comprises the treatment of one of the compounds of the present invention with a nucleophilic nucleophilic moiety Rearrangement is the course of reaction except where a bromide or iodide is employed, in which case, reduction occurs. The introduced nucleophilic moiety locates at either the 5 or 7 positions, depending on the identity of R and the nucleophilic moiety.

In the instance of either reduction or introduction of the nucleophile, the products are useful, in accordance with prior teachings, as herbicides. See US. Pat. No. 60

Two synthetic routes are useful in the preparation of the starting l-hydroxy compounds:

In a first synthetic route, the compounds are prepared by reduction of a precursor of the formula:

NO; 3. I

The reaction is believed to go through several intermediates which are not isolatable, but yields as product the desired l-hydroxy-lH-imidazo(4,5-b)pyridine compound. The reaction conditions are not critical; however, it is generally preferred to employ as reducing agent two moles of hydrogen per mole of the nitropyridineamine, in the presence of a minor amount of a catalyst comprising a noble metal, preferably palladium. In a representative synthesis, 1-hydroxy-6- chloro-2-( trifluoromethyl l H-imidazo( 4,5-b )pyridine was prepared as follows:

5-Chloro-3-nitro-2-(trifluoroacetamido)pyridine (2.0 grams) was hydrogenated with two moles of hydrogen in ethanol containing 0.5 gram of 5 percent palladium on carbon. The resulting reaction mixture was filtered and evaporated to separate the desired 6- chlorol -hydroxy-2-(trifluoromethyl l H-imidazo- (4,5-b)pyridine compound which, after recrystallization from benzene melted at 26870C. Analysis,

Cale: C, 35.39; H, l.27; N, 17.69.

Found: C, 35.59; H, 1.45; N, 17.77.

In a second synthetic route, a suitable l-hydroxy compound is itself utilized as a precursor to other l-hydroxy compounds which serve as starting materials for the preparation of the compounds of the present invention. In this route, the initially employed l-hydroxy compound is subjected to reactions to introduce onto the pyridine ring one or more desired groups and/or to convert one 

2. The compound of claim 1 which is 1-methoxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.
 3. The compound of claim 1 which is 1-ethoxy-2,6-bis-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.
 4. The compound of claim 1 which is 1-allyloxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.
 5. The compound of claim 1 which is 1-isopropoxy-6-chloro-2-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine.
 6. The compound of claim 1 which is 1-methoxy-2,6-bis-(trifluoromethyl)-1H-imidazo(4,5-b)pyridine. 